牺牲模板法合成钴基硫化物和氢氧化物空心纳米棱柱材料及其电化学性能研究

发布时间：2018-07-12 20:11

本文选题：纳米材料 + 空心棱柱　；参考：《山东大学》2017年硕士论文

【摘要】：随着人们对能源的需求日益增加以及传统的能源模式因环境和储量问题无法满足新的要求,锂离子电池、超级电容器以及电催化储能技术应运而生。近年来,过渡金属化合物,尤其过渡金属硫化物和氢氧化物,作为锂离子电池、超级电容器或电催化材料引起了人们广泛的研究兴趣。以过渡金属硫化物和氢氧化物为活性材料在能量转化与储存等领域取得了较大的进展,然而材料的电化学性能仍需进一步提高。本论文采用牺牲模板法,通过液相反应合成了双金属硫化物和层状双金属氢氧化物空心棱柱纳米材料,然后对其上述电化学性能测试,结果如下:第一,钴锰双金属硫化物空心棱柱/石墨烯复合材料的制备及其锂电性能研究。以醋酸钴(Co(OAC)2·4H20)和醋酸锰(Mn(OAC)2 · 4H20)为原料,利用其在石墨烯的乙醇分散液中的水解,以聚乙烯吡咯烷酮(PVP)为形貌控制剂,采用溶剂热法,成功合成了被石墨烯包覆的、分散良好的、具有均一尺寸的碱式醋酸钴锰纳米棱柱/石墨烯复合材料((Co,Mn)5(OH)2(CH3COO)8·2H20/RGO)。将制备的碱式醋酸钴锰纳米棱柱/石墨烯复合材料作为模板和金属源,将硫代乙酰胺作为硫源,通过水热反应制备了完整复制模板原有形貌的CoS2@MnS/RGO空心纳米棱柱复合材料。成功制备完好复制模板原有形貌的空心纳米棱柱的关键在于:恰当控制棱柱模板的溶解和硫代乙酰胺水解释放硫离子的速度。将制得的CoS2@MnS/RGO空心纳米棱柱复合材料为活性物质用于LIBs负极测试。结果表明该复合材料不仅拥有较高的比容量、优异的性能稳定性,而且具有很好的倍率性能。在100mA g-1 200mA g-1甚至1000mA g-1的测试电流下均展现了比传统商业化石墨电极更高的比容量。而该材料之所以展现如此优异的LIBs性能主要归功于以下三方面:(1)材料的空心结构大大缩短了 Li+的扩散距离;(2)较高的比表面积增大了电极-电解质溶液的有效接触;(3)2D RGO增大了其导电性和结构强度。第二,钴基层状双金属氢氧化物(LDHs)空心纳米棱柱的制备及其电化学性能研究。以醋酸钴(Co(OAC)2·4H20)为原料,利用其在乙醇溶液中的水解,以聚乙烯吡咯烷酮(PVP)为形貌控制剂,采用溶剂热法,成功合成了分散良好、尺寸均一的碱式醋酸钴(Co5(OH)2(CH3COO)8 · 2H20)纳米棱柱。通过加入不同的过渡金属硝酸盐,以合成的碱式醋酸钴纳米棱柱为模板和钴源,成功制备了Ni-Co LDH和Co-Co LDH两种空心棱柱材料。本文合成的两种空心LDHs不仅成功复制了模板的棱柱形貌,而且壁壳由纳米薄片组成,使得空心结构更加坚固。成功制备完好复制模板原有形貌的空心纳米棱柱的关键在于:恰当调节模板-碱式醋酸钴的刻蚀、LDH成分的沉积及Co2+的氧化等反应之间的平衡关系。将所得的两种钻基LDHs材料作为电化学活性材料用于超级电容器和电催化产氧(OER)性能的测试,并对其性能进行了对比。实验结果证明,LDHs空心纳米棱柱不仅有良好的超级电容器性能,而且在电催化析氧方面也展现出优异的电催化活性。
[Abstract]:With the increasing demand for energy and the fact that the traditional energy mode is unable to meet new requirements because of the environment and reserves, lithium ion batteries, supercapacitors and electrocatalytic energy storage technology have come into being. In recent years, transition metal compounds, especially transition metal sulfide and hydroxides, are used as lithium ion batteries, supercapacitors. Great progress has been made in the field of energy conversion and storage with transition metal sulfides and hydroxides as active materials. However, the electrochemical properties of the materials still need to be further improved. This paper uses the sacrificial template method to synthesize the bimetallic sulfide through the liquid phase reaction. The results are as follows: first, the preparation of cobalt manganese bimetal sulfide hollow prism / graphene composite and its lithium electrical properties. Using cobalt acetate (Co (OAC) 2. 4H20) and manganese acetate (Mn (OAC) 2. 4H20) as raw materials, they are used in graphene The hydrolysis in the ethanol dispersing solution, with polyvinylpyrrolidone (PVP) as the morphology control agent, has been successfully synthesized by the solvothermal method, which has been successfully synthesized by the graphene coated, dispersed and homogeneous cobalt manganese nanoprism / graphene composite (Co, Mn) 5 (OH) 2 (CH3COO) 8. 2H20/RGO). Graphene composite is used as a template and metal source, and thioacetamide is used as a sulfur source. By hydrothermal reaction, the CoS2@MnS/RGO hollow nano prism composite material has been prepared by hydrothermal reaction. The key to successfully prepare the hollow nanoscale with the original morphology of the complete replicating template lies in the proper control of the dissolution and sulfur of the prism template. The rate of thioacetamide was hydrolyzed to release sulfur ions. The CoS2@MnS/RGO hollow nano prism composite was used as the active substance for the test of LIBs negative electrode. The results showed that the composite not only had high specific capacity, excellent performance stability, but also had good multiplier performance. Test in 100mA g-1 200mA g-1 even 1000mA g-1 The ratio of current to the traditional commercial fossil ink electrode is higher than that of the traditional commercial fossil ink electrode. The excellent performance of the LIBs is mainly attributed to the following three aspects: (1) the hollow structure of the material greatly shortens the diffusion distance of the Li+; (2) the higher specific surface area increases the effective contact of the electrode electrolyte solution; (3) the increase of 2D RGO Second, the preparation and electrochemical properties of cobalt base like double metal hydroxide (LDHs) hollow nano prism were prepared and studied. Using cobalt acetate (Co (OAC) 2. 4H20) as raw material, using its hydrolysis in ethanol solution, polyvinylpyrrolidone (PVP) as the morphology control agent and solvent thermal method successfully synthesized and dispersed well. Good, size homogeneous cobalt acetate (Co5 (OH) 2 (CH3COO) 8. 2H20) nanoprism. By adding different transition metal nitrates and synthesizing alkaline cobalt nanoprism as template and cobalt source, two hollow prism materials of Ni-Co LDH and Co-Co LDH have been successfully prepared. Two kinds of hollow LDHs synthesized in this paper have not only successfully replicated the template. The shape of the prism, and the wall of the shell is made of nanoscale, makes the hollow structure stronger. The key to successfully preparing the hollow nanoscale with the original morphology of the template is to properly regulate the etching of the template alkaline cobalt acetate, the deposition of LDH components and the oxidation of the Co2+. The two kinds of drill base LDHs materials will be obtained. As an electrochemical active material, the performance of supercapacitor and electrocatalytic oxygen production (OER) was tested and its performance was compared. The experimental results showed that the LDHs hollow nano prism not only had good supercapacitor performance, but also showed excellent electrocatalytic activity in the field of electrocatalytic oxygen evolution.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1

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